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>2.1. Invoking the script</H1
><P
>Having written the script, you can invoke it by <TT
CLASS="USERINPUT"
><B
>sh
	scriptname</B
></TT
>,

	  <A
NAME="AEN300"
HREF="#FTN.AEN300"
><SPAN
CLASS="footnote"
>[1]</SPAN
></A
>

	or alternatively <TT
CLASS="USERINPUT"
><B
>bash scriptname</B
></TT
>. (Not
	recommended is using <TT
CLASS="USERINPUT"
><B
>sh &#60;scriptname</B
></TT
>,
	since this effectively disables reading from
	<A
HREF="ioredirintro.html#STDINOUTDEF"
><TT
CLASS="FILENAME"
>stdin</TT
></A
>
	within the script.) Much more convenient is to make
	the script itself directly executable with a <A
HREF="basic.html#CHMODREF"
>chmod</A
>.

	<P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
>Either:</DT
><DD
><P
><TT
CLASS="USERINPUT"
><B
>chmod 555 scriptname</B
></TT
> (gives
	      everyone read/execute permission)
	        <A
NAME="AEN315"
HREF="#FTN.AEN315"
><SPAN
CLASS="footnote"
>[2]</SPAN
></A
>
	      </P
></DD
><DT
>or</DT
><DD
><P
><TT
CLASS="USERINPUT"
><B
>chmod +rx scriptname</B
></TT
> (gives
	      everyone read/execute permission)</P
><P
><TT
CLASS="USERINPUT"
><B
>chmod
	      u+rx scriptname</B
></TT
> (gives only the
		script owner read/execute permission)</P
></DD
></DL
></DIV
>
      </P
><P
>Having made the script executable, you may now test it by
	<TT
CLASS="USERINPUT"
><B
>./scriptname</B
></TT
>.
	
	  <A
NAME="AEN327"
HREF="#FTN.AEN327"
><SPAN
CLASS="footnote"
>[3]</SPAN
></A
>

	If it begins with a <SPAN
CLASS="QUOTE"
>"sha-bang"</SPAN
> line, invoking the
	script calls the correct command interpreter to run it.</P
><P
>As a final step, after testing and debugging,
	you would likely want to move it to <TT
CLASS="FILENAME"
>/usr/local/bin</TT
> (as
	<I
CLASS="FIRSTTERM"
>root</I
>, of course), to make the script
	available to yourself and all other users as a systemwide
	executable.  The script could then be invoked by simply typing
	<B
CLASS="COMMAND"
>scriptname</B
> <B
CLASS="KEYCAP"
>[ENTER]</B
> from the
	command-line.</P
></DIV
><H3
CLASS="FOOTNOTES"
>Notes</H3
><TABLE
BORDER="0"
CLASS="FOOTNOTES"
WIDTH="100%"
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
WIDTH="5%"
><A
NAME="FTN.AEN300"
HREF="invoking.html#AEN300"
><SPAN
CLASS="footnote"
>[1]</SPAN
></A
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
WIDTH="95%"
><P
>Caution: invoking a <I
CLASS="FIRSTTERM"
>Bash</I
>
	  script by <TT
CLASS="USERINPUT"
><B
>sh scriptname</B
></TT
> turns off
	  Bash-specific extensions, and the script may therefore fail
	  to execute.</P
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
WIDTH="5%"
><A
NAME="FTN.AEN315"
HREF="invoking.html#AEN315"
><SPAN
CLASS="footnote"
>[2]</SPAN
></A
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
WIDTH="95%"
><P
>A script needs <I
CLASS="FIRSTTERM"
>read</I
>, as
		well as execute permission for it to run, since the shell
		needs to be able to read it.</P
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
WIDTH="5%"
><A
NAME="FTN.AEN327"
HREF="invoking.html#AEN327"
><SPAN
CLASS="footnote"
>[3]</SPAN
></A
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
WIDTH="95%"
><P
>Why not simply invoke the script with
	  <TT
CLASS="USERINPUT"
><B
>scriptname</B
></TT
>? If the directory you
	  are in (<A
HREF="internalvariables.html#PWDREF"
>$PWD</A
>) is where
	  <TT
CLASS="FILENAME"
>scriptname</TT
> is located, why doesn't
	  this work? This fails because, for security reasons, the
	  current directory (<TT
CLASS="FILENAME"
>./</TT
>)
	  is not by default included in a user's <A
HREF="internalvariables.html#PATHREF"
>$PATH</A
>. It is therefore necessary to
	  explicitly invoke the script in the current directory with
	  a <TT
CLASS="USERINPUT"
><B
>./scriptname</B
></TT
>.</P
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